Solar Powered tracker

Hi there!

I was wondering what solar panel do i need to run a nano and 2 sg90 servos? The information i've gotten is the sg90 servos operates around 550mA and stall at 750mA. i have a 11.5V 150mA solar panel. Both are Voc and Isc values. If it is not sufficient to power up the components, may i know what panel do i need to minimally run them?

Your question lacks key facts.

Will you have a battery in between your solar panel and the system? If not how is it going to work when there is no light or it’s a bit cloudy?

Will the motors run permanently or only from time to time?

-> You need to find out how much power your system requires and what’s the peak value - then design around this.

If you don’t know take a large 100W solar panel and an solar adapter and it will work to a certain point but if you don’t have a way to store the energy then poor lighting == no system running

An unknown factor is what is the size and chemical characteristics of the battery that will be used?

A Li will operate differently than a LiFePo4 or Lead Acid battery. I'd not use a Li battery in a solar project. OK, I did try using Li batteries but that proved unreliable.

I ran 2 metal geared servos that were powered off/on when the sun was up down. It took 30Watts of solar in poor sun conditions to keep the 12V 16Ah LiFePo4 charged. I figured 20Watts would do the trick but had a 10W solar panel laying around not doing anything so I added that to the project for extra measure.

Thank you for your reply. I plan to run it as a short demo for a project.

Thank you for your reply. I plan to run it as a short demo for a project. Lets say a 10W 12V panel is use to run the system, for a short duration about 5-10mins , will it be able to run it? For now I want it to run smoothly as a self sufficient solar powered tracker. Additional components would be a future addition.

With additional circuitry, on a bright sunny day, a 10W 12V panel would be able to fully power two SG-90 servos (3 watts each) and an Arduino Nano.

Do you get to decide the day of the demo? You’ll need a good sunshine

awesome! I do hope not to use another panel as this is just going to be a simple project.

Yes, I do. In case of bad weather condition such as rainy days, I was told to have a recorded demo prepared beforehand.

can a 10W solar panel at a clear day run two mg 946r servo motor which has a stall current at 1.2A at 5V each without battery?

Because the solar output is so inconsistent, I’d say no - on a professional level.
It might work under ideal conditions, but under anything less, it would be unreliable.

If you put something like this in…
12V 15W solar charger
Along with a suitably sized SLA battery, you’d be pretty happy.

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how about at a clear sunny day? it will not run for long. just a couple of minutes for demonstration purposes.

Also the solar panel is a 10W 18V 0.55A which i am thinking of connecting it to a 5V 2.5A Buck Converter with a 6.5-27VDC Input.

If you want to risk it, go ahead.
Wire up the solar & regulator first, check the voltages, then if it doesn’t work, you can start over again.

That probably won't work for even one servo, but it will be a good learning experience.

May i know what's a good panel for it? is solar panel really that weak?damn

In the US, solar panels are rated for voltage on a open circuit, meaning the volt meter is the ONLY thing connected to the panel wires. The rated current is with the panel wires SHORTED together. That makes it really hard to determine what the panel will produce with something like a buck converter connected to the wires.

Solar panels act more like current sources than voltage sources. So, they are a poor match for anything that is intended to operate in a specific voltage range, like a servo.

Solar panels are great for recharging batteries, which are much more useful for powering electronics. Use a 6V NiMH battery pack as the intermediate in your project, rather than a buck converter, and you will be fine.

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thanks for your feedback! can i use a 6V 4.5AH sealed lead acid battery ?

Check the servo ratings. The terminal voltage of fully charged "6V" lead acid batteries can be over 7V.

You can add one or more high current diodes between the battery and the servo, to drop this voltage (by 0.7 to 1V per diode) if necessary.